New York City police said on Tuesday they were investigating suspicious mailings of white powder received by several financial companies.
"None of the material tested so far has tested positive for any dangerous substance, and was found in some instances to be flour or corn starch," said police spokesman Paul Browne.
He said envelopes containing Zip-lock bags with the powder inside and greeting cards without a message and postmarked from Hartford, Conn., were sent to the companies on Monday and Tuesday. He did not name the companies that received the mailings.
In 2001, powdery anthrax sent in letters to news organizations and government offices in New York, Florida, Washington and elsewhere killed five people and made at least 17 people ill.
Suspicious white powders were found in buildings occupied by the Daily News, the Associated Press and The New York Times last year but were found not to be hazardous.